Rolling-up polymer films which contain active substances, to produce forms of medication, is known. EP 0 209 212, EP 0 086 997, and EP 0 122 574 describe embedding active substances in polymer films for delayed release. These films are processed individually or in comminuted form into capsules, or compressed into tablets. Delayed release is essentially determined by the type of film and by the size of its surface area. At the beginning of active substance release, the entire film surface is soon in contact with the digestive fluids, and therefore is available to release the active substance.
EP-A 010 987 describes rolling-up a film which contains an active substance, for the administration of veterinary medications to ruminants, where the primary form is supposed to unroll after administration and expand to form an enlarged secondary form. The purpose of the volume expansion is so that the medication remains in the rumen for a longer time. The release of the active substance then also takes place from the entire surface area of the film, which is accessible to the digestive juices. A laminate which is produced with a pressure-sensitive adhesive, in accordance with EP-A 363 187, is also supposed to act in a similar manner. This is also described in EP-A 350 188.
It has also been proposed to introduce rolled-up films which contain active substances into body cavities, e.g., EP-A 447 719, specifically for therapy of middle-ear infections, or, according to JP-Abstract 82-90967 (Derwent), intravaginally for administration of spermicides as a contraceptive. In these cases, only local release of active substance is intended, and here again, one can assume that the film roll will soon expand because it absorbs moisture, and that the active substance will be released from the loosened film laminate.
A form of medication which floats in the stomach is described in EP-A 326 816. Here, polymer films enriched with the active substance are processed to produce various shapes, which are supposed to have an extended dwell time in the stomach because of the use of porous materials in them, along with other materials, or inclusion of air. As a further development of this idea, DE 4419818 mentions rolled films which remain in the stomach for an extended period of time because they unfold, and are intended to pass through the pylorus passage only with difficulty because of their size, which is greater than 5 cm.sup.2. Here again, the entire surface area of the film becomes available for active substance release after the film has unfolded or expanded.